Electronic start-stop regenerative repeater



Jan. 15, 1963 H. F. wlLDER ETAL ELECTRONIC START-STOP REGENERATIVEREPEATER Filed July 11, 1961 4 Sheets-Sheet 1 INVENTORS H. F WILDER R.K. LEWIS ATTORNEY w25: mazo @mit l Jan. 15, 1963 H. F. WILDER ETALELECTRONIC START-STOP REGENERATIVE REPEATER Filed July 11, 1961 4Sheets-Sheet 2 INVENTORS H. F. WILDER R. K. LEWIS ATTORNEY Jan.. 15,1963 1-1. F. w11 D1= R ETAL 3,073,898

ELECTRONIC START-STOP REGENERATIVE REPEATER Filed July 11, 1961 4Sheets-Sheet 3 l 1 I 1 I RElsT 1 1 1 CE l 1 I l I 1 l I 1 1 l 1 1 RESTINVENTORS H. F. WILDER R. K. LEWIS ATTORNEY.

I I I I I I I I 1 I I I TIM E IN MILLISECONDS ,11111ww..11111v1- 11111111 1 1 1 1 1 111 1 1111 111 1111111L11111 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 11 1 1 1 11IL11 r WIr l R IIIIII II II IIIIIIIIIII IIIIIIIIIII 111I.m||+vT R s 11n11111111111 1 111 1111 111 -111111111 if 1 1111 1- 1 S s E I1l111| 1| 11|I111l|L11ll I I l I Ill |IlR11110 United States igatent@ffice arrasar Patented Jan. 15, 1963 3,973,898 ELECTRONIC START-STOPREGENERATIWE REPEATER Harold F. Wilder, Wycoif, NJ., and Roy K. Lewis,

Brooklyn, NSY., assignors to The Western Union Telegraph Company, NewYork, NX., a corporation of New York Filed July 11, 1961, Ser. No.123,315 19 Claims. (Cl. 178-70) This invention relates generally to astart-stop regenerative repeater network and more particularly to anetwork which will assume an operative state during receipt of acharacter signal and an inoperative state during the absence of acharacter signal.

It is an object of this invention to provide a device which isselectively sensitive to the occurrence and abscence of a charactersignal.

It is ano-ther object of this invention to provide a device which cananticipate the termination of a character signal without counting.

It is still another object of this invention to provide a device whichcan be set selectively to conform to the speed and code of the characterreceived.

It is also an object of this invention to provide a device whichutilizes components which are readily available in convenient values,sizes and weights.

It is an additional object of this invention to provide a device whichis reliable in operation and economical to build.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the apparatus becomes better understoodby reference to the following detailed description when considered inconnection with the accompanying drawings wherein:

- FIG. 1 is a partial schematic drawing of the structure of thisinvention;

FIG. 2 is also a partial schematic drawing of structures of thisinvention, which, when positioned to the right of FIG. l forms anembodiment of the present invention;

FIG. 3 illustrates graphically the wave forms occurring within thisinvention; and

FIG. 4 illustrates graphically other wave forms occurring within thisinvention.

Similar reference characters refer to similar 'parts throughout theseveral views ofthe drawing.

Briefly, in this invention a repeater means such as a start-stopregenerative repeater is coupled to receive permutation code signalssuch as the start-stop Baudot type of code. The lirst pulse signal orbit of each character fed to the repeater means is also fed to a triggermeans which initiates operation of a baud oscillator means and anauxiliary oscillator means through an oscillator control means. Thefrequency of the baud oscillator is usually equal to the frequency ofoccurrence of the bits of a character. Thus, when operating with astart-stop system employing a seven and a fraction unit code wherein astart pulse is received at the beginning of each tive unit character anda rest pulse representing a marking condition is received at the end ofeach character, the baud oscillator means will generate seven cyclesstarting with the occurrence of the start pulse (the rst pulse of thecharacter) and ending with the occurrence of the rest pulse (the lastpulse of the character). The frequency of the auxiliary oscillator issix-sevenths that of the baud oscillator. Thus, the oscillators areiirst in phase at the beginning of the lirst cycle, and again at the endof the seventh cycle of the baud oscillator means and the sixth cycle ofthe auxiliary oscillator means. The occurrence of phase synchronism ofthe two oscillators at the end of seven cycles for the baud oscillatormeans and six cycles for the auxiliary oscillator means is utilized tocondition the oscillator control means to stop the operation of the twooscillators during the rest pulse.

Thus, in this invention the signal from the baud oscillator means iscompared with the signal from the auxiliary oscillator means-theoccurrence of in phase synchronism of the two oscillators being utilizedto stop the operation of the baud oscillator means at the termination ofthe character.

As used throughout the specification and claims, the terms mark andspace refer to two opposite electrical conditions. In the telegraph artthe term mark generally refers to a negative battery on a line or aclosed line, while space customarily refers to a positive battery oropen line. In a carrier system these terms will refer to two differentfrequencies. However, in practice it sometimes occurs that a markcondition will be positive battery while a space will represent negativebattery. Therefore, the present specification uses these terms, mark andspace, in their broad sense as representing any two different electricalconditions selectively used to transmit intelligence. Also, the termline as used throughout the specification and claims is intended toinclude any connecting means between telegraph stations such as wires,cables or radio channels.

Detailed Description of Invention With reference to FIGS. l and 2 thereis disclosed structure in accordance with the principle of this invention. An input terminal 10 coupled to receive signals for regenerationis coupled through an impedance 12 to a grid terminal 14 of an electronvacuum tube 16 which supports an anode terminal 18 and a cathodeterminal 20. Input terminal 10 is also coupled through resistors 22, 24,and 26 connected in series to the grid terminal 28 of an electron vacuumtube 36 which supports an anode terminal 32 and a cathode terminal 34.The junction of the resistors 22, 24 is coupled to the cathode terminals20, 34; and the junction of the resistors 24, 26 is coupled to a groundterminal. A source of positive potential is coupled to the anodeterminal 18 through im pedance .36 and to the anode terminal 32 throughimpedance 38.

The grid terminal 14 of tube 16 is connected through the seriescombination of impedances 40, 42 to the anode terminal 44 of anelectronic vacuum tube 46 which supports a grid terminal 48 and acathode terminal 50; and the grid terminal 28 of tube 30 is connectedthrough the series combination of impedances 52, 54 to the anodeterminal 56 of an electronic vacuum tube 58 which supports a gridterminal 60 and a cathode terminal 62. The junction of the impedances40, 42 is coupled to the junction of the impedances 52, 54 through twocapacitors 64,l

66 connected in series, and the terminal common to the two capacitors64, 66 is connected to a ground terminal.

The anode terminal 32 of tube 30 is coupled through the seriescombination of an impedance 68 and a diode iti to the grid .terminal 48;and anode terminal 18 of tube 16 is coupled through the seriescombination of an impedance 72 and a diode 74 to the grid terminal 60.The cathode terminal of diode 74 is coupled to the cathode terminal ofdiode '70 through two impedances 76, 78 connected in series; and theanode terminals of the diodes 70, 74 are coupled together through twoimpedances 80, 82 connected in series. A source of nega-tive potentialis coupled to the terminal common to the impedances 76, 78; and to theterminal common to the impedances 80, 82.

The anode terminal 56 of tube 58 is coupled to the grid terminal 48 oftube 46 through the resistor 84 and capacitor 86 coupled in shunt; andthe anode terminal 44 of tube 46 is coupled to the grid terminal 60 oftube a 58 through the resistor 88 .and capacitor 90 coupled in shunt.The tubes 16, 30, 46, and 58, and the interconnecting componentscomprise a repeater means 92.

rl`he output signals from the repeater means 92 are fed to a drive means94 which is coupled to energize selectively an output means 96.

The anode terminal 56 of tube 58 is coupled through an impedance 98 tothe grid terminal 100 of an electron vacuum tube 102 which supports gridterminal 104, grid terminal 106, anode terminal 108, and cathodeterminal 110; and the anode terminal 44 of tube 46 is coupled throughimpedance 112 to grid terminal 114 of an electron vacuum tube 116 whichsupports grid terminal 118, grid terminal 120, anode terminal 122, andcathode terminal 124. Grid terminal 106 is coupled to cathode terminal110; and grid terminal 120 is coupled to cathode terminal 124. A sourceof positive potential is coupled through an impedance 126 to the gridterminal 104 of tube 102 and to the grid terminal 118 of tube 116. Thegrid terminal 100 is coupled to grid terminal 114 through resistors 128,130 connected in series. A source of negative potential is connected tothe terminal common to the resistors 128, 130, and to the cathodeterminals 110, 124 through a resistor 132.

The anode terminal 108 of tube 102 is coupled through one winding of apolar relay to a source of positive potential; and the anode terminal122 of tube 116 is coupled through the other winding of the polar relayto the source of positive potential. The polar relay which, in thisapplication is referred to as output means 96, supports two stationarycontacts which cooperate with a movable contact. One stationary contactis coupled to a source of positive potential, and the other stationarycontact is coupled to a source of negative potential. An output terminal134 is connected to the movable contact. Energization of one coil orwinding will urge the movable Contact towards one stationary contact,and energization of the other coil or winding will urge the movablecontact towards the other stationary contact. Thus, the potentialpresent on the output terminal 134 is determined by selectivelyenergizing one or the other winding of the relay-the energization of onewinding resulting in the presence of a positive potential on the outputterminal 134 and energization of the other winding resulting in thepresence of a negative potential on the output terminal 134.

The cathodes 50, 62 of tubes 46, 58 are coupled together and to thecathode terminal 136 of dual triode vacuum tube 138 having anothercathode terminal 140, grid terminals 142, 144, and anode terminals 146,148. The anode terminal 146 is coupled to the anode terminal 56 of tube58. A source of positive potential is coupled through two resistors 150,152 connected in series to the grid terminal 142 and a source ofnegative potential is coupled to the cathode -terminal 136 through aresistor 154 and to the grid terminal 142 through a resistor 156. Theanode terminal 148 is coupled to a ground terminal and to the gridterminal 144 through a resistor 158. A source of negative potential iscoupled through a resistor 160 to the cathode terminal 140 and through aresistor 162 to the grid terminal 144.

The cathode terminal 140 of tube 138 is coupled to the cathode terminals164, 166 of a dual triode vacuum tube 168 which supports grid terminals170, 172, and anode terminals 174, 176. A source of negative potentialis coupled to grid terminal 170 through resistor 17S and to gridterminal 172 through resistor 180. The anode terminals 174, 176 arecoupled together and to a ground terminal through a tirst oscillatormeans 97 composed of a center tapped coil 184 positioned in parallelwith a capacitor 186 and the left triode section `of a tube 192. Theanode terminals 174, 176 of tube 168 are also coupled through a resistor188 to the grid terminal 190 of a dual triode vacuum tube 192 whichsupports another grid terminal 194, cathode terminals 196, 198, andanode terminals 200, 202. The center tap of the coil 184 is coupledthrough two resistors 204, 206 connected in series to the grid terminal194. The junction of the resistors 204, 206 is coupled to the cathodeterminal 196. The cathode terminal 198 is coupled to a ground terminal,and the grid terminal 194 is coupled through a resistor 208 to a sourceof positive potential. The source of positive potential is also coupleddirectly to the anode terminal 200 and through a resistor 210 to theanode terminal 202. The anode terminal 202 is coupled through the seriescombination of a capacitor 210 and resistor 212 to the grid terminal 214of a vacuum tube 216 which supports a cathode terminal 218 and an anodeterminal 220. Additionally, the anode terminal 202 is also coupledthrough the parallel combination of a resistor 222 and a diode 224 tothe junction of resistors 82, 68 through a capacitor 226, and to thejunction of resistors 80, 72 through a capacitor 228.

A source of positive potential is coupled to the cathode terminal 218 oftube 216 through a resistor 230, and a source of negative potential iscoupled to the cathode terminal 218 through a resistor 232. The junctionof the capacitor 210 and resistor 212 is coupled to the cathode terminal218 through a resistor 234 connected in shunt with a diode 236. The gridterminal 214 is coupled through a resistor 238 in series with acapacitor 240 to the plate terminal 242 of a dual triode vacuum tube 244which supports another anode terminal 246, grid terminals 248, 250, andcathode terminals 152, 254.

A source of positive potential is coupled directly to anode terminal246, to anode terminal 242 through resistor 256, and to grid terminal250 through resistor 258. Cathode terminal 254 is coupled to groundterminal and cathode terminal 2r 2 is coupled through resistor 260 togrid terminal 250.

Grid terminal of tube 168 is coupled through resistors 262 and 264 tothe grid terminal 266 of a dual triode vacuum tube 268 which supportsanother grid terminal 270, cathode terminals 272, 274, and anodeterminals 276, 278. A source of negative potential is coupled to gridterminal 266 through resistor 280, to cathode terminals 272, 274 throughresistor 282, and to grid terminal 270 through resistor 284. Anodeterminal 278 is coupled to a ground terminal and through resistor 286 togrid terminal 270. The right triode section of tube 268 and itsassociated components functions as a voltage regulator. l

Anode terminal 276 is coupled to a ground terminal through a secondoscillator means 288 composed of a coil 290 having an upper half and alower half connected in shunt with a capacitor 292, and the left triodeof tube 244. The anode terminal 276 of tube 268 is also coupled to thegrid terminal 248 of tube 244 through a resistor 294; and the center ofthe coil 290 is coupled through a resistor 296 to the cathode terminal252.

Returning briey to tube 216, the junction of the resistor 238 and thecapacitor 240 is coupled to the cathode terminal 218 through a resistor298 and a diode 300 connected in shunt. A source of positive potentialis coupled to the anode terminal 220 through a resistor 302, and theanode terminal 220 is coupled through a resistor 304 to the gridterminal 306 of a dual triode vacuum tube 308 which supports anothergrid terminal 310, cathode terminals 312, 314, and anode terminals 316,318.

Cathode terminals 312, 314 are coupled together and to a groundterminal. A source of positive potential is coupled to anode terminal318 through a resistor 320, and to anode terminal 316 through a resistor322. Grid terminal 310 is coupled through a resistor 324 to a source ofnegative potential, through a resistor 326 to anode terminal 318, andthrough a resistor 328 to the anode terminal 32 of vacuum tube 30. Gridterminal 306 is coupled through the series combination of a resistor 330and a capacitor 332 to the anode terminal 44 of tube 46, and

to a source of negative potential through a resistor 334 connected inshunt with a diode 336.

Anode terminal 316 of tube 308 is coupled to the junction of resistor262 with resistor 264, and through a diode 336to the junction ofresistors 150, 152 and through a diode 338 to the anode terminal 340 ofa dual triode vacuum tube 342 which supports another anode terminal 339,grid terminals 344, 346, and cathode terminals 348, 350.

With reference to tube 342, cathode terminals 348, 350 are connectedtogether and coupled to a ground terminal through a resistor 352. Gridterminal 346 is coupled to a ground terminal through a resistor 354 andto the anode terminal 339 through a capacitor 356. A source of positivepotential is coupled to anode terminal 340 through a resistor 356, anodeterminal 339 through a resistor 358, and to grid terminal 344 through aresistor 360. A capacitor 362 is interposed between anode terminal 340and grid terminal 344. The anode terminal 339 is coupled through aresistor 364 in shunt with a capacitor 366 to the grid terminal 172 oftube 168, and grid terminal 344 is coupled through a capacitor 368 tothe anode terminal 318 of tube 308.

A source of negative potential is coupled through two resistors 368, 370connected in series to the gridterminal 214 of tube 216. A resistor 372is interposed between the junction of the resistors 368, 370 and theanode terminal 318 of tube 308.

'Ihe function of the parts of FIGS. 1 and 2 is indicated by means offunctional titles assigned to particular parts indicated by boXes formedby dash lines. The network incorporating the tubes 16, 30, 46 and 58 isthe repeater means 92 and operates the output means 96 through theoutput drive means 94. The network incorporating the tubes 168 and 268,and the right triode section of tube 138 is referred to as theoscillator control means 93-the right triode section of tube 138 beingfurther referred to as iirst voltage regulator 100, the right triodesection of tube 268 being further referred to as second voltageregulator 103, and the right triode section of tube 168 being furtherreferred to as oscillator brake means 103; the left triode section oftube 138 and its associated structure comprises a mark signal generatingmeans 87; the tubes 308 and 216 and their associated structure comprisesa trigger means 91 which supports a dilferentiator means 83; and thetube 342 and its supporting structure comprises a delay means 95.Additionally, a resonant circuit and its associated drive means--theleft triode section of tube 192 comprises a lirst oscillator means 97;another resonant circuit and its associated drive means-the left triodesection of tube 244 comprises a second oscillator means 288; andnetworks each incorporating a triode tube comprises a first square wavegenerator 99, and a second square wave generator 101.

Now, with reference to the operation of the structure of this inventionas illustrated in FIGS. 1 and 2, and to the associated waveformsillustrated in FIG. 3 the input terminal is coupled to receiveintelligence bearing pulse signals consisting of mark pulse signals andspace pulse signals.

To facilitate the description of the operation of this invention it isassumed the space pulse signals have a positive polarity and that markpulse signals have a negative polarity relative to ground. A typicalinput signal is illustrated as Waveform A in FIG. 3.

The waveforms illustrated in FIG. 3 are for the 7.42 unit code and thosein FIG. 4 are for the 8.00 unit code. Each curve illustrated in theFIGS. 3 and 4 represents a signal further identified as follows:

A-Input signal.

B-Signal at anode terminal 316 of left triode section of tube 308.

C-Signal from square wave generator 99.

D-Tirning pulse signals from baud oscillator.

E-Signals from the baud oscillator.

F-Signal from the auxiliary oscillator.

G-Signal from square wave generator 101.

H-Negative timing pulse signals from auxiliary oscillator.

.'I-Combination of negative pulse signals from the baud and auxiliaryoscillators fed to grid terminal 214 of tube 216.

K-Signal at anode terminal 318 of right triode section of tube 308.

L-Signal at anode terminal 220 of tube 216.

M-Signal fed to grid terminal of tube 46 showing signal from plate oftube 58 and pulse signals from baud oscillator.

N-Output signal.

O-Signal on anode terminal 340 of right triode section of tube 342.

Description of Operation Each signal fed to the input terminal 10produces a potential across the resistors 22, 24. If the received signalis a marking pulse signal then terminal 11 will be more negative thanterminal 13, and terminal 13 will be more negative than terminal 15.Thus, the signal fed through the resistor 12 to the grid terminal 14 ofvacnum tube 16 is more negative than the signal fed to the cathodeterminal 20 of tube 16, and tube 16 is urged to its cut-off state.However, the signal fed to the grid terminal 28 of vacuum tube 30 ispositive relative to the cathode terminal 34 of tube 30, and tube 30becomes conductive.

A positive pulse signal from the plate or anode of the cut-olf tube 16is fed to the grid terminal 60 of tube 58 through resistor 72 and diode74. A negative pulse signal is fed to the grid terminal 48 of tube 46through resistor 68 and diode 70 from the lowered plate potential oftube 30. These pulse signals are not of suflicient amplitude to aect thestates of the tubes 46 and 58. However, when a positive pulse signalfrom the first oscillator means 97 through the iirst square wavegenerator 99 is fed through the capacitor 228 and is added to thepositive pulse signal from tube 16, the resultant is suicient to drivetube 58 to its conductive state. Multibrator action drives tube 46 toits nonconductive state via capacitor 86 and resistor 84.

The positive potential now present at the plate or anode terminal 44 oftube 46 is fed through resistor 112 to the grid terminal 114 of the tube116. The current which flows in the plate circuit of tube 116 urges theouput means 96 which can be a polar relay to feed a marking pulse signalto the output terminal 134. The decrease of the plate potential of thetube 58 fed to tube 1 02 through resistor 98 urges tube 102 to itsnonconductive state.

Now, if the signal fed to the input terminal is a spacing pulse signal,junction 11 becomes positive relative to junctions 13 and 15 and tube 16is urged to its conductive state while tube 30 is urged to itsnonconductive or cut-off state. A positive pulse signal is fed from tube30 through resistor 68 to the grid terminal 48 of tube 46, however, thestates of the tubes 46 and 58 will not change until a positive potentialpulse signal generated by the first oscillator means 97 and shaped bythe first square wave generator 99 is fed through the capacitor 226 totube 46. This pulse signal generated by the oscillator adds to thepositive pulse signalV from the tube 30 to drive tube 46 to itsconductive state. Activation of tube 46 operating through resistor 88and capacitor 90 urges tube 58 to its nonconductive state. Waveform Millustrates the signal fed to the grid terminal 48 of tube 46 and showsthe pulse signals from the tube 30 and the added pulse signals or spikesgenerated by the iirst oscillator means 97 and shapedyin the lirstsquare wave generator 99.

To initiate operation of the oscillators, the positive pulse signal fromthe plate terminal 32 of tube 30 is fed through resistor 323 to drivethe left triode section of tube 308 into its conductive state. WaveformB illustrates the signal present on the plate terminal 316 of tube 308.The drop in potential present at the plate terminal 316 of tube 308which results when it assumes its conductive state urges the left triodesection of tube 168 into its non-conductive state. The steady D.C. whichwas flowing from the source of negative potential through re sistor 160,the left triode section of tube 168, and the coil 184 is now stopped andoscillations in the coil 184 begin at a rate determined by the values ofthe coil 184 and capacitor 186. Waveform E illustrates the signalgenerated by the first oscillator means 97. The output signal from thisfirst oscillator means (baud oscillator) is fed to the grid terminal 194of the right triode section of tube 192. This right section of tube 192is the first square wave generator 99 and converts the output signalfrom the oscillator 97 into square Waves. Waveform C illustrates thesignal from the first square wave generator 99. The positive pulsesignal of the square wave will occur exactly one-half of a signal pulselength after the incoming pulse signal. The positive pulse signals passthrough diode 224 to the capacitors 226 and 228 where they aredifferentiated to obtain spike pulse signals. The positive going spikesignal in combination with the positive pulse signal from tube 30 willurge tube 46 to its conductive state. Either signal separately will noturge tube 42 to its conductive state-both signals are required. Thediode 224 is oriented to provide a very high resistance path fornegative pulse signals from the first square wave generator 99 thuscompelling them to pass through and be attenuated by the resistor 222 toprevent the negative pulse signals from changing the states of the tubes46 and/or 58. The positive spike pulse signals only are used to triggerthe tubes 46 or 58.

The left triode section of tube 308 must now be maintained in aconductive state for the duration of the occurrence of the characterbeing received or seven cycles of the baud oscillator 97 when the 7.42unit code is being used. When the tube 46 is driven to its conductivestate (one half cycle after the start pulse enters the tube 30) anegative pulse signal is fed through capacitor 332 and resistor 330 tothe grid terminal 306 of the right triode section of tube 308 to drivethe triode to its nonconductive state. Immediately, the plate potentialrises and this rise in potential is fed through resistor 326 to the gridterminal 310 to lock the left triode section in its conductive state.The left triode section of tube 308 maintains its conductive state andit will not be changed by the subsequent occurrence of negative pulsesignals from the plate terminal 32 of tube 30. At the same instance thatthe right triode section of tube 308 becomes nonconductive a positivepulse signal is fed through resistors 372 and 370 to the grid terminal214 of tube 216, and tube 216 becomes conductive. The decrease in platepotential now present on the plate terminal 220 of tube 216 is fedthrough resistor 304 to the grid terminal 306 to lock the right triodesection of tube 308 in its nonconductive state. Waveform K illustratesthe signal present at the plate terminal 318 (right triode section) oftube 308.

At the same time that operation of the rst oscillator means (baudoscillator) 97 was initiated the negative pulse signal from the lefttriode section of tube 308 is fed to and cuts off the left triodesection of tube 238 which initiates activation of the second oscillatormeans (auxiliary oscillator) 288. The second oscillator means has afrequency which is six-sevenths ((71) that of the first oscillator means(baud oscillator) 97. The two oscillators are in phase only at thebeginning of the iirst cycle and at the end of the seventh cycle of thebaud oscillator and the sixth cycle of the auxiliary oscillator.Waveform E illustrates the signal from the baud oscillator, and waveformF illustrates the signal from the auxiliaryY oscillator.

The negative pulse signals generated by the baud oscillator are fed tothe tube 216 after they are first fed to the right triode section oftube 192 which is the first square wave generator 99 and they areconverted to square waves and then fed to the capacitor 210 and resistor212 in the differentiator means 83 where they are differentiated. Thepositive pulse `signals are attenuated through the action of the diode236 and, therefore, do not appear at the grid terminal 214 of tube 216.

The negative pulse signals fed to the grid terminal 214 of tube 216 donot have a magnitude which is suicient to drive tube 216 to its inactiveor cut-cti state. However also appearing at the grid terminal 214 oftube 216 are the negative pulse signals generated by the auxiliaryoscillator which are first fed to the right triode section of tube244-the second square wave generator 101, where they are converted tosquare waves and then to the capacitor and resistor 238 in thedifferentiator means 83 where they are differentiated. The positivepulse signals originating from the auxiliary oscillator are attenuatedthrough the action of the diode 300 and, therefore, do not appear at thegrid terminal 214 of the tube 216.

The pulse signals fed to the grid terminal 214 of tube 216 from theauxiliary oscillator are out of phase with those from the baudoscillator and, by themselves, are also of a magnitude which is notsutiicient to drive the tube 216 to its cut-off state.

The negative signals illustrated in waveform D from the baud oscillatorare fed to the grid terminal 214 of tube 216; and waveform H illustratesthe negative signals from the auxiliary oscillator which are fed to thegrid terminal 214 of tube 216. Waveform I illustrates the combinedsignals from the baud and auxiliary oscillators received by the gridterminal 214 of tube 216.

After the occurrence of the seventh cycle for the baud oscillator andthe sixth cycle for the auxiliary oscillator the negative signals willbe exactly in phase and will produce a signal having a maximum magnitude(see waveform J). The magnitude of the resultant signal produced by thesimultaneous occurrence of the two signals is sufficient to drive thetube 216 to its cut-off state.

Cut-oif of tube 216 produces a rise in its plate potential which is fedto and produces a positive pulse signal at the grid terminal 306 of theright triode section of tube 303. This positive pulse signal drives theright triode section of tube 308 into its conductive state. Uponassuming a conductive state the plate potential of the right triodesection of tube 308 is lowered and produces a negative pulse signalwhich is fed to the grid terminal 214 of tube 216 to maintain tube 216in its nonconductive or cut-ofi state. Waveform L illustrates the signalwhich appears at the plate or anode terminal of tube 216. At the sameinstant a negative pulse signal from the right triode section of tube308 is also fed to the grid terminal 310 of the left triode section oftube 308 to drive this section into its nonconductive or cut-off state.The potential fed from the anode terminal 32 of tube 30 through resistor328 to the grid terminal 310 of the left triode section of tube 308 isalso negative as the presence of a marking input signal from the signalrest pulse will drive tube 30 into its conductive state. The urging ofthe left triode section of tube 308 into its cutaof state generates, atthe anode terminal 316, a positive pulse signal which is fed to the gridterminal of the left triode section of tube 168 and to the grid terminal266 of the left triode section of tube 268. This generated positivepulse signal urges each of the associated triodes (left triode sectionof tube 168 and tube 268) to its conductive state and a steady currentis fed through the coils of the baud and auxiliary oscillators to stopthem from oscillating. This is illustrated in waveforms E and F.

The next occurring spacing pulse signal fed to the input terminal 10will initiate operation of the oscillator as described. However, thesignal which appears at the output terminal 134 is displaced cne-half ofa pulse g.. width relative to the received signal. N-the signal on theoutput terminal 134.

The stopping and starting of the oscillators always insures propertiming of the output signals.

For the 7.42 unit code the oscillators arel stopped for 0.42 of the restpulse signal. When operating this invention with even unit codes (forexample 7 or 8 unit codes) an extra fraction of a rest pulse signal inwhich to stop the oscillators must be provided. In the use of thisinvention with 8.00` unit code, the oscillator generates seven (7)cycle-s and is stopped during the rest or eighth (8th) pulse signal.However, the rest pulse is not regenerated by the oscillators, but isproduced by other means.

When the left triode section of tube 308 cuts off and stops theoperation of the oscillators, a positive pulse signal is fed throughdiode 336 and resistor 152 to the grid terminal 142 to drive the lefttriode section of tube 138 into its conductive state. It should be notedthat this triode-the left triode section of tube l3S is coupled inparallel with triode 58. Thus, when the left triode section of tube 138becomes conductive the tube 58 cuts oii and causes a mark signal toappear at the output terminal 134.

The oscillators stop operation as soon as the seventh pulse signal ofthe input or received signal is received by the regenerator (FIG. 4,waveforms E and F) and, as indicated previously the operation of thetubes 46, 58 lags behind the operation of the tubes 16, 3i) by one-halfof a pulse length. Therefore, the left triode section of tube 138 mustbe kept from conducting for one-half of a pulse length to prevent thesixth pulse of the output signal from being shortened when the lefttriode section of tube 138 conducts. Tube 342 is a one shotmultivibrator utilized as a delay means to delay the operation of theleft triode section of tube 138.

When the right triode section of tube 368 conducts (when ltheoscillators are stopped) a negative pulse signal is fed throughcapacitor 368 to the rigid terminal 344 of the left triode section oftube 342, and this triode section cuts off, `and a positive pulse signalis fed through capacitor 356 to the grid terminal 346 to drive the righttriode section of tube 34E-2 to its conductive state. Now, a negativecharge on capacitor 362 locks the left triode section of `tube 342 toits nonconductive state. The capacitor 362 begins to recharge positivelythrough the resistor 369 until (after one-half of a pulse length) itaccumulates `a positive charge surlicient to urge the left triodesection of tube 342 to its conductive state. When the left triodesection of tube 342 becomes conductive it feeds a negative pulse signalthrough capacitor 356 to the grid terminal 3416 and the right triodesection of tube 342 cuts-off.

When the right triode section of -tube 36E-2 started to conduct, itsplate potential decreased (FIG. 4, waveform O) and a negative pulsesignal was fed through diode 338 and overrode the positive potentialthrough the diode 336 to maintain .the grid terminal 142 at a negativepotential to prevent the left triode section of tube 13S fromconduct-ing. However, at the termination of onehalf pulse length whenthe right triode section of tube 342 stopped conducting the gridterminal 142 went positive and the left triode section of tube 138conducts to generate-the marking rest pulse signal.

The right triode section of tube 68 is utilized as an oscillator brakemeans and operates only when even unit codes are being received. lf theincoming signals received are heavily spacing biased tube 30 will not bedriven to its conductive state by a marking rest pulse signal at the endof 7 cycles and, therefore, the operation of the oscillators will not beterminated at the proper time. A positive pulse signal will be fedthrough resistor 328 to the grid terminal 310 of the left triode sectionof tube 3tlg to nullify the negative pulse signal fed to the gridterminal 310 through the resistor 326.

See waveform 10 Unfortunately, in this instance the first oscillatormeans could generate a fraction of an oscillation which could causepremature turn-over of the tubes 58 and 46 thereby reducing the lengthof `the seventh pulse signal (when 8.00 unit code is being utilized).The right triode section of tube 168- prevents the occurrence of thiscondition by assuming its conductive state when the left triode sectionof tube 342 is in its cut-off state. This condition occurs at the end ofthe seventh cycle. Activation of the oscillator brake means lr03 -stopsthe operation of the first oscillator means. The right triode section oftube 16S continues to conduct until the tube 342 `flips back. However,before the tube 342 liips back the left Itriode section of tube 168 hastaken over the braking function as the left triode section of tube 308is now in its cut-oli state.

The right triode section of tube 138 and the right triode section oftube 268 are inverse -ampliiiers used as voltage regulators to maintainthe cathode voltage of their respective oscillator brake means constant.

During the armature travel time of 4the relay feeding the signal to theinput terminal 1t), particularly when this travel time is increasedbecause of the effects of interfering line c-urrents, there is anabsence of signal voltage on the input terminal 10. In the timing pulsesignals from the square wave generators is received by the gridterminals of the tubes 46, 58 during this interval a signal can not beregenerated. Therefore, an inverse feed-back network is utilized .toanticipate the polarity change across terminals il, t3, and 15 caused bythe input relay travel. The inverse feed-back network comprises theresistors 52, 54 and the resistors 40, 42.

This inverse feed-back network insures the appearance of a potential a-tthe grid terminals of tubes 16 and 3i). This potential yanticipates thenew output potential of the relay land will cause tubes .116 and 39 tochange from a conducting state -to la nonconducting state (or viceversa) only during the absence of a potential between terminals it), 13,and 15.

Naturally, in the construction of this invention all vacuum tubesreferred yto as dual triodes can be replaced by Itwo `single triodesand, in a like manner two single (triode vacuum tubes can be replaced bya dual triode vacuum tube. a clear yet concise Iand full description ofthis invention the theater circuits of each tube and the usual sourcesof positive and negative potentials have not been shown.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. lit is therefore to beunderstood that within lthe scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

l. A regenerative repeater comprising a first oscillator means togenerate a signal having a iirst frequency, a second oscillator means togenerate a signal having .a second frequency different from the firstfrequency, an oscillator control means coupled to initiate and terminateoperation of -said first and second oscillator means, a trigger meansinterposed between said first and second oscillator means and saidoscillator control means to terminate operation of said iirst and secondoscillator means upon the occurrence of in phase pulse signals from saidfirst and second oscillator means, -a repeater means selectivelyconditioned by said rst oscillator means to pass received line pulsesignals coupled to said trigger means to initiate operation of saidfirst and second oscillator means upon receipt of a line pulse signal,output means, and drive means interposed between said repeater means andsaid output means.

2. A regenerative repeater comprising a first capacitor; a first coilcoupled to said first capacitor to provide a rst network having a rstresonant frequency; a second capacitor; a second coil coupled to saidsecond capacitor Furthermore, in an attempt to maintain' to provide asecond network having a second resonant frequency; an oscillator controlmeans coupled to initiate and terminate operation of said first andsecond networks; a trigger means interposed between said first andsecond networks and said oscillator control means to 4terminateoperation of said first and second networks upon the occurrence of inphase pulse signals from said first and second networks; a repeatermeans selectively conditioned by said first network to pass receivedline pulse signals coupled to said trigger means to initiate operationof said first and second networks upon receipt of a line pulse signal;output means; and drive means interposed between said repeater means andsaid output means.

3. A regenerative repeater comprising a first oscillator means togenerate a signal having a first frequency, a second oscillator means togenerate a signal having a second frequenc, an oscillator control meanscoupled to initiate and terminate operation of said first and secondoscillator means, a first network fed by said first and secondoscillator means to indicate the occurrence of in phase signals fromsaid first and second oscillator means, a second network fed by saidfirst network coupled to said oscillator control means to terminateoperation of said first and second oscillator means upon the occurrenceof in phase pulse signals from said first and second oscillator means, arepeater means selectively conditioned by said first oscillator means topass received line pulse signals coupled to said second network toinitiate operation of said first and second oscillator means uponreceipt of a line pulse signal, output means, and drive means interposedbetween said repeater means and said output means.

4. A regenerative repeater comprising a first capacitor, a first coilcoupled to said first capacitor to provide a first network having afirst resonant frequency; a second capacitor; a second coil coupled tosaid second capacitor to provide a second network having a secondresonant frequency; an oscillator control means coupled to initiate andterminate operation of said first and second networks; a third networkfed by said first and second networks to indicate the occurrence of inphase signals from said first and second networks; a fourth network fedby said third network coupled to said oscillator control means toterminate operation of said first and second networks upon theoccurrence of in phase pulse signals from said first and secondnetworks; a repeater means selectively conditioned by said first networkto pass received line pulse signals coupled to sai-d fourth network toinitiate operation of said first and second networks upon receipt of aline pulse signal; output means; and drive means interposed between saidrepeater means and said output means.

5. A regenerative repeater comprising a first oscillator means togenerate a signal having a first frequency, a first square wavegenerator fed by said first oscillator means, a second oscillator meansto generate a signal having a second frequency, a second square wavegenerator fed by said second oscillator means, an oscillator controlmeans coupled to initiate and terminate operation of said first andsecond oscillator means, a trigger means interposed between said rst andsecond square wave generators and said oscillator control means toterminate operation of said first and second oscillator means upon theoccurrence of in phase pulse signals from said first and secondoscillator means, a repeater means selectively conditioned by the signalfrom said first oscillator means through said first square wavegenerator to pass received line pulse signals coupled to said triggermeans to initiate operation of said first and second oscillator meansupon receipt of a line pulse signal, output means, and drive meansinterposed between said repeater means and said output means.

6. A regenerative repeater comprising a first capacitor; a rst coilcoupled to said first capacitor to provide a first network having afirst resonant frequency; a first square wave generator fed by saidfirst network; a second capacitor; a second coil coupled to said secondcapacitor to provide a second network having a second resonantfrequency; a second square wave generator fed by said second network; anoscillator control means coupled to initiate and Iterminate operationlof said first and second networks; a trigger means interposed betweensaid first and second square wave generators and said oscillator controlmeans to terminate operation of said first and second networks upon theoccurrence of in phase pulse signals from said first and secondnetworks; a repeater means selectively conditioned by the signal fromsaid first network through said first square wave generator to passreceived line pulse signals coupled to said trigger means to initiateoperation of said first and second networks upon receipt of a line pulsesignal; output means; and drive means interposed between said repeatermeans and said output means.

7. A regenerative repeater comprising a first oscillator means togenerate a signal having a first frequency, a rst square wave generatorfed by said first oscillator means, a second oscillator means togenerate a signal having a second frequency, a second square wavegenerator fed by said second oscillator means, an oscillator controlmeans coupled to initiate and terminate operation of said first andsecond oscillator means, a first network fed by said first and secondsquare wave generators to indicate the occurrence of in phase signal, asecond network fed by said first network coupled to said oscillatorcontrol means to terminate operation of said first and second oscillatormeans upon the occurrence of in phase pulse signals from said first andsecond square wave generators, a repeater means selectively conditionedby said first square wave generator to pass received line pulse signalscoupled to said second network to initiate operation of said first andsecond oscillator means upon receipt of a line pulse signal, outputmeans, and drive means interposed between said repeater means and saidoutput means.

8. A regenerative repeater comprising a first capacitor; a first coilcoupled to said first capacitor to provide a first network having afirst resonant frequency; a first square wave generator fed by saidfirst network; a second capacitor; a second coil coupled to said secondcapacitor to provide a second network having a second resonantfrequency; a second square wave generator fed by said second network; anoscillator control means coupled to initiate and terminate operation ofsaid first and second networks; a third network fed by said first andsecond square wave generators to indicate the occurrence of in phasesignals; a fourth network fed by said third network coupled to saidoscillator control means to terminate operation of said first and secondnetworks upon the occurrence of in phase pulse signals from said firstand second square wave generators; a repeater means selectivelyconditioned by said first square wave generator to pass received linepulse signals coupled to said fourth network to initiate operation ofsaid first and second networks upon receipt of a line pulse signal;output means; and drive means interposed between said repeater means andsaid output means.

9. A regenerative repeater comprising Ia first oscillator means togenerate a signal having a first frequency, a first square wavegenerator fed by said first oscillator means, a second oscillator meansto generate a signal having a second frequency, a second square wavegenerator fed by said second oscillator means, an oscillator controlmeans coupled to initiator and terminate operation of said first andsecond oscillator means, a trigger means interposed between said firstand second square wave generators and said oscillator control means toterminate operation of said first and second oscillator means upon theoccurrence of in phase pulse signals from said first and secondoscillator means, a first differentiator interposed ybetween said firstoscillator means and said trigger means, a second differentiatorinterposed between said second oscillator means and said trigger ieans,a repeater means selectively conditioned by the signal from said firstoscillator means through said first fil 13 square wave generator to passreceived line pulse signals coupled to said Itrigger means to initiateoperation of said first and second oscillator means upon receipt of aline pulse signal, output means, and drive means interposed between saidrepeater means and said Output means.

10. Aregenerative repeater comprising a first capacitor; a first coilcoupled to said first capacitor to provide a firs-t network having afirst resonant frequency; a first square wave generator fed lby saidfirst network; a second capacitor; a second coil coupled to said secondcapacitor to provide a second network h-aving a second resonantfrequency; a 4second square wave generator fed by said second network;an oscillator control means coupled to initiate and terminate :operationof said first and second networks; a trigger means interposed betweensaid first and second square wave generators and said oscillator controlmeans to terminate operation of said first and second networks upon ,theoccurrence of in phase pulse signals from said first and secondnetworks; a first differentiator interposed between said first squarewave generator and said trigger means; a second -differentiatorinterposed between said second square wave generator and said triggermeans; a repeater means selectively conditioned by the signal from saidfirst network through said first square wave generator to pass receivedline pulse signals coupled to said trigger means to initiate operationof said first and second networks upon receipt of a line pulse signal;output means; and drive means interposed between saidrepeater means andsaid output means.

11. A regenerative repeater comprising a first oscillator means 4togenerate a signal having a firs-t frequency; a first square wavegenerator fed by said first oscillator means; a second oscillator meansto generate a signal having a second frequency; a second square wavegenerator fed by said second oscillator means; an oscillator controlmeans coupled to initiate and terminate operation of said first andsecond oscillator means; a first network fed by said first and secondsquare wave generators to indicate the occurrence of in phase signals; afirst differentiator interposed between said first network and saidfirst square wave genera-tor; a second differentiator interposed betweensaid first network and said second square wave generator; a secondnetwork fed by said first network ycoupled to said oscillator controlmeans to terminate operation of said rst and second oscillator meansupon the occurrence of in phase pulse signals from said first and secondsquare wave generators, a repeater means selectively lconditioned bysaid first square wave generator to pass received line pulse signalscoupled to said second network to initiate operation of said first andsecond oscillator means upon receipt of a line pulse signal; outputmeans; and drive means interposed between said repeater means and saidoutput means.

l2. A regenerative repeater comprising a first capacitor, a first coilcoupled to said first capacitor to provide a first network having afirst resonant frequency; a first square wave generator fed by saidfirst network; a second capacitor; a second coil coupled to said secondcapacitor to provide a -second network having a second reso-nantfrequency; a second square wave generator fed by said second network; anoscillator control means coupled to initiate and terminate operation ofsaid first land second networks; a third network `fed 'by said first andsecond square wave generators to indicate the occurrence of in phasesignals; a first difierentiator interposed between said third networkand said rst square wave generator; a second differentiator interposedbetween said 'third network `and said second square Wave generator; afourth network fed by said 4third network coupled to said oscillatorcontrol means to terminate operation of said first and lsecond networksupon the occurrence of in phase pulse signals from said first and secondsquare wave generators, a repeater means selectively conditioned by saidfirst square wave generator to pass received line pulse 114 signalscoupled to said fourth network to initiate operation of said first andsecond networks yupon receipt of a line pulse signal; output means; fanddrive means interposed between said repeater means Iand said outputmeans.

13. A regenerative repeater comprising a first oscillator means togenerate a sifnal having a first frequency; a second oscillator means togenerate a signal having a second frequency; an oscillator .controlmeans coupled to initiate land terminate operation of said first andsecond oscillator means; a first network fed by :said first and secondoscillator means to indicate the occurrence of in phase signals fromsaid first and second oscillator means, a second network fed by saidfirst network coupled to said `oscillator control means t-o terminateoperation of said first and second oscillator means upon the occurrenceof in phase pulse signals from said first and second oscillator means, arepeater means selectively conditioned by said first oscillator means topass'received line pulse signals coupled to said second network toinitiate operatio-n of said first and second oscillator means uponreceipt of a `line pulse signal; output means; drive means interposedbetween said repeater means and said output means; mark signalgenerating means fed by said trigger means coupled to feed a generatedmark pulse signal to said repeater means; `and delay means coupled toretard the operation lof said mark signal generating means.

14. A regenerative repeater comprising a first capacitor; a first coilcoupled to said first capacitor to provide a first network having afirst resonant frequency; a second capacitor; a second coil coupled tosaid second capacitor to provide a second network having a secondresonant frequency; an oscillator control means coupled to initiate andterminate operation of said first and second networks; a third networkfed by said first and second networks to indicate the occurrence of inphase signals from said first and second networks; a fourth network fedby said third network coupled to said oscillator control means toterminate operation of said first and second networks upon theoccurrence of in phase pulse signals from said first and secondnetworks, a repeater means selectively conditioned by said first networkto pass received line pulse signals coupled to said fourth network toinitiate operation of said first and second networks upon receipt of aline pulse signal; output means; drive means interposed between saidrepeater means and said output means; mark signal generating means fedby said fourth network coupled to feed a generated mark pulse signal tosaid repeater means; and delay means coupled to retard the operation ofsaid mark signal generating means.

15. A regenerative repeater comprising a rst oscillator means togenerate a signal having a first frequency; a first square wavegenerator fed by said first oscillator means; a second oscillator meansto generate a signal having a second frequency greater than the firstfrequency; a second square wave generator fed by said second oscillatormeans; an oscillator control means coupled to initiate and terminateoperation of said first and second oscillator means, a trigger meansinterposed between said first and second square wave generators and saidoscillator control means to terminate operation of said first and secondoscillator means upon the occurrence of in phase pulse signals from saidfirst and second oscillator means, a repeater means selectivelyconditioned by the signal from said first oscillator means through saidfirst square wave generator to pass received line pulse signals coupledto said trigger means to initiate operation of said first and secondoscillator means upon receipt of aline pulse signal; output means; drivemeans interposed between said repeater means and said output means; marksignal generating means fed by said trigger means coupled to feed agenerated mark pulse signal to said repeater means; and delay meanscoupled to retard the operation of said mark signal generating means.

16. A regenerative repeater comprising a rst oscillator means togenerate a signal having a first frequency; a first square wavegenerator fed by said first oscillator means; a second oscillator meansto generate a signal having a second frequency; a second square wavegenerator fed by said second oscillator means; an oscillator controlmeans coupled to initiate and terminate operation of said first andsecond oscillator means; a first network fed by said first and secondsquare wave generators to indicate the occurrence of in phase signals; asecond network fed by said first network coupled to said oscillatorcontrol means to terminate operation of said first and second oscillatormeans upon the occurrence of in phase pulse signals from said first andsecond square wave generators, a repeater means selectively conditionedby said first square wave generator to pass received line pulse signalscoupled to said second network to initiate operation of said first andsecond oscillator means upon receipt of a line pulse signal; outputmeans; drive means interposed between said repeater means and saidoutput means; mark signal generating means fed by said second networkcoupled to feed a generated mark pulse signal to said repeater means;and delay means coupled to retard the operation of said mark signalgenerating means.

17. A regenerative repeater comprising a first oscillator means togenerate a signal having a first frequency; a first square wavegenerator fed by said rst oscillator means; a second oscillator means togenerate a signal having a second frequency; a Second square wavegenerator fed by said second oscillator means; an oscillator controlmeans coupled to initiate and terminate operation of said first andsecond oscillator means; a trigger means interposed between said firstand second square wave generators and said oscillator control means toterminate operation of said first and second oscillator means upon theoccurrence of in phase pulse signals from said first and secondoscillator means; a first diferentiator interposed between said firstoscillator means and said trigger means; a second differentiatorinterposed between said second oscillator means and said trigger means;a repeater means selectively conditioned by the signal from said firstoscillator means through said first square Wave generator to passreceived line pulse signals coupled to said trigger means to initiateoperation of said first and second oscillator means upon receipt of aline pulse signal; output means; drive means interposed between saidrepeater means and said output means; mark signal generating means fedby said trigger means coupled to feed a generated mark pulse signal tosaid repeater means; and a one shot multivibrator coupled to retard theoperation of said mark signal generating means.

18. A regenerative repeater comprising a first oscillator means togenerate a signal having a first frequency; a first square wavegenerator fed by said first oscillator means; a second oscillator meansto generate a signal having a second frequency; a second square wavegenerator fed by said second oscillator means; an oscillator controlmeans coupled to initiate and terminate, operation of said first andsecond oscillator means; a trigger means interposed between said firstand second square wave generators and said oscillator control means toterminate operation of said first and second oscillator means upon theoccurrence of in phase pulse signals from said first and secondoscillator means; a repeater means selectively conditioned by the signalfrom said first oscillator means through said first square wavegenerator to pass received line pulse signals coupled to said triggermeans to initiate operation of said first and second oscillator meansupon receipt of a line pulse signal; output means; drive meansinterposed between said repeater means and said output means; marksignal generating means fed by said trigger means coupled to feed agenerated mark pulse signal to said repeater means; delay means coupledto retard the operation of said mark signal generating means; andoscillator brake means coupled to said first oscillator means.

19. A regenerative repeater comprising a first oscillator means togenerate a signal having a first frequency; a first square wavegenerator fed by said first oscillator means; a second oscillator meansto generate a signal having a second frequency; a second square wavegenerator fed by said second oscillator means; an oscillator controlmeans coupled to initiate and terminate operation of said first andsecond oscillator means; a triggermeans interposed between said firstand second square wave generators and said oscillator control means toterminate operation of said first and second oscillator means upon theoccurrence of in phase pulse signals from said first and secondoscillator means; a first differentiator interposed between said firstoscillator means and said trigger means; a second differentiatorinterposed between said second oscillator means and said trigger means;a repeater means selectively conditioned by the signal from said firstoscillator means through said first square wave generator to passreceived line pulse signals coupled to said trigger means to initiateoperation of said first and second oscillator means upon receipt of aline pulse signal; output means; drive means interposed between saidrepeater means and said output means; mark signal generating means fedby said trigger means coupled to feed a generated mark pulse signal tosaid repeater means; a one shot multivibrator coupled to retard theoperation of said mark signal generating means; and oscillator brakemeans coupled to said first oscillator means.

Oberman Nov. 4, 1958 Gardberg July 12, 1960

1. A REGENERATIVE REPEATER COMPRISING FIRST OSCILLATOR MEANS TO GENERATEA SIGNAL HAVING A FIRST FREQUENCY, A SECOND OSCILLATOR MEANS TO GENERATEA SIGNAL HAVING A SECOND FREQUENCY DIFFERENT FROM THE FIRST FREQUENCY,AN OSCILLATOR CONTROL MEANS COUPLED TO INITIATE AND TERMINATE OPERATIONOF SAID FIRST AND SECOND OSCILLATOR MEANS, A TRIGGER MEANS INTERPOSEDBETWEEN SAID FIRST AND SECOND OSCILLATOR MEANS AND SAID OSCILLATORCONTROL MEANS TO TERMINATE OPERATION OF SAID FIRST AND SECOND OSCILLATORMEANS UPON THE OCCURRENCE OF IN PHASE PULSE SIGNALS FROM SAID FIRST ANDSECOND OSCILLATOR MEANS, A REPEATER MEANS SELECTIVELY CONDITIONED BYSAID FIRST OSCILLATOR MEANS TO PASS RECEIVED LINE PULSE SIGNALS COUPLEDTO SAID TRIGGER MEANS TO INITIATE OPERATION OF SAID FIRST AND SECONDOSCILLATOR MEANS UPON RECEIPT OF A LINE PULSE SIGNAL, OUTPUT MEANS, ANDDRIVE MEANS INTERPOSED BETWEEN SAID REPEATER MEANS AND SAID OUTPUTMEANS.